Weakness in working memory predicts progression of alcohol use in early adolescents

Weakness in a cognitive skill called “working memory” predicts both the initiation and the escalation of alcohol use in adolescents ages 10 to 15, according to a longitudinal study by researchers at the Annenberg Public Policy Center of the University of Pennsylvania and the Children’s Hospital of Philadelphia.

Working memory is the cognitive function that allows us to deliberate before acting, a process that is critical for making decisions and planning behavior. It depends heavily on parts of the brain that control impulses and allow one to consider the consequences of behavior. Past research has suggested that alcohol use during adolescence causes a reduction in this ability by adversely affecting the development of the adolescent brain.

“By repeating assessments on the same children over four years during early adolescence, this project is the first to show that individual differences in working memory precede and predict early alcohol onset and progressive drinking behaviors in adolescents,” noted Atika Khurana, lead author of the study. Khurana conducted this study while she was a post-doctoral fellow at the University of Pennsylvania; she is now an Assistant Professor in the Dept. of Counseling Psychology & Human Services at the University of Oregon. “It is still quite likely that heavy alcohol use during adolescence is responsible for decrements in this ability, however our research shows that at least some of these weaknesses are already present before adolescents even begin using alcohol.”

Recently published in the journal Addiction, the study followed a community cohort of 358 adolescents from the Philadelphia area over a period of four years. The researchers conducted extensive neuropsychological testing of the children beginning at ages 10 to 12, prior to their initiation of any alcohol use, and at each annual follow-up. Assessments of impulsivity, sensation seeking, and alcohol use were also conducted at all four time points.

Youth who had weak working memory exhibited greater levels of impulsivity as assessed by tendencies that reflect lack of self-control, such as acting without thinking and inability to delay gratification. Adolescents with higher levels of impulsivity were more likely to have lower working memory ability, and also more likely to report early initiation and progression of alcohol use.

In contrast, adolescents who reported attraction to exciting activities, a personality trait known as sensation seeking, were not more likely to use alcohol once the effect of impulsivity was controlled for. This is consistent with the finding that unlike youth that are impulsive, sensation seekers tend to have stronger (and not weaker) working memory. Research with animals also suggests that although sensation seekers are likely to experiment with drugs, it is impulsivity that more strongly predicts adverse effects of drug use.

Early use of alcohol is a strong predictor of later alcohol abuse. According to the CDC, excessive use of alcohol accounts for nearly half of traffic accidents in persons ages 20 to 44 and half of all homicides in the U.S.

“Because early alcohol use is a predictor of later alcohol abuse, our findings suggest that children with weak working memory ability and associated forms of impulsivity could be targeted for early intervention to prevent later problems,” said Dan Romer, co-author of the study and director of the Adolescent Communication Institute at the Annenberg Public Policy Center of the University of Pennsylvania. “The findings also suggest that adolescents high in sensation-seeking, often thought to be at risk, may actually be somewhat protected by their better working memory ability.”

“Recent research suggests that working memory ability can be improved with training. This suggests a promising avenue to intervene to reduce impulsive tendencies associated with weak working memory, and consequently to prevent alcohol abuse as teens mature,” Khurana added. “This is a possibility that should be studied in future research.”

“While working memory abilities continue to develop during adolescence, these skills depend on early experience and learning, so interventions should be applied as early as possible to maximize their effect,” says Laura Betancourt, the senior clinical researcher on the team from Children’s Hospital of Philadelphia.

The research was supported by the National Institute of Drug Abuse; however, the conclusions are solely those of the authors.